POS0527 THE PRESENCE OF MONOSODIUM URATE DEPOSITS IN THE JOINTS OF PATIENTS WITH ASYMPTOMATIC HYPERURICEMIA IS ASSOCIATED WITH A HIGHER CARDIOVASCULAR RISK, BUT NOT WITH MORE ADVANCED KIDNEY DAMAGE
Authors: R. Gancheva, A. Koundurdjiev, T. Kundurzhiev, Z. Kolarov, P. Peteva, I. Koundurdjieva, L. Marinchev
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Epidemiological studies conducted in patients (pts) from the general population and pts with chronic renal failure have shown that uric acid is an independent risk factor for the development and progression of kidney disease. Uric acid damages the kidneys by causing systemic and glomerular hypertension. Hyperuricemia is connected to arteriolosclerosis, characterized by arterial wall thickening and hyalinosis. <h3>Objectives</h3> To evaluate the association between asymptomatic hyperuricemia and renal damage and to establish whether the presence of monosodium urate (MSU) deposits in the joints of these pts is related to more advanced renal alterations. <h3>Methods</h3> This was a single-center cross-sectional study, including 73 consecutive pts divided into 34 pts with osteoarthritis (controls), 25 subjects with asymptomatic hyperuricemia and no ultrasound (US) evidence of MSU crystals in the joints and 14 individuals with asymptomatic hyperuricemia and MSU deposits in the joints. Pts underwent bilateral US examination of the joints of the hands, elbows, knees, ankles, feet and the kidneys. Measurements of the joints were conducted with a high-frequency linear transducer 4-15 MHz. The existence of double contour sign, intra-tendinous MSU aggregates, "snow storm", tophi, tophi with erosions, or a combination of these US features was assessed. Kidneys were examined with 3.5 MHz transducer, working with pulse Doppler frequency of 2.5 MHz. Renal length, parenchymal thickness and echogenicity were determined. The presence or absence of nephrolithiasis was reported. By means of the value of renal resistive index (RRI) we judged for intrarenal blood flow. Statistical analyzes were done by One-Sample Kolmogorov-Smirnov, t-test, Chi-square or Fisher`s exact test. <h3>Results</h3> The distribution of males and females (p=0.441), smokers and non-smokers (p=0.147), pts with arterial hypertension and normotensive individuals (p=0.298) as well as subjects with diabetes and without diabetes (p=0.775) and pts with dyslipidemia and normal lipid levels (p=1.000) was similar among the groups. The proportion of pts who had suffered with cardiovascular event was the highest in the group of asymptomatic hyperuricemia with MSU deposits in the joints (21.4%) compared to the group of osteoarthritis (14%) and hyperuricemia without MSU crystals in the joints (0%), (p=0.048). In the group of osteoarthritis the share of pts with eGFR &lt; 90 ml/min was the lowest (5.9%) in comparison to the group of hyperuricemia without MSU deposits in the joints (29.2%) and hyperuricemia with crystals in the joints (46.2%), (p=0.005). The percentage of obese pts was the highest in hyperuricemia with MSU crystals in the joints (57.1%), but without reaching a significant difference with hyperuricemia without crystals in the joints (40%) and the group of osteoarthritis (29.4%), (p=0.195). The echogenicity of the kidneys (p=0.630) and the distribution of nephrolithiasis (p=0.596) was equal among the groups. Pts with hyperuricemia and MSU deposits in the joints compared to those with osteoarthritis had higher BMI (mean±SD; 31.79±5.92 kg/m<sup>2</sup> vs 28.06±4.27 kg/m<sup>2</sup>, p=0.018) and smaller kidney size (mean±SD; 55.36±5.58 mm vs 59.58±5.12 mm, p=0.015). The comparison of hyperuricemia without MSU deposits in the joints to osteoarthritis group demonstrated a significant difference only in the age (mean±SD; 49.7±16.4 years vs 61.5±9.4 years, p=0.001). Finally, the comparison of the two groups with hyperuricemia showed that subjects with MSU deposits in the joints had higher BMI (mean±SD; 31.79±5.92 kg/m<sup>2</sup> vs 28.26±4.41 kg/m<sup>2</sup>, p=0.041) with no difference in the age (p=0.072), kidney size (p=0.141), RRI (p=0.296), eGFR (p=0.528) and thickness of renal parenchyma (p=0.232). <h3>Conclusion</h3> Hyperuricemia independently of the presence of articular crystals is associated with similar kidney damage. Cardiovascular risk is higher when MSU crystals are found by US in the joints. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.